Condensation Temperature Research Articles

Hybrid air conditioning and seawater desalination system assisted by solar energy: thermoeconomic investigation and optimization

The demand for freshwater has become progressively critical due to population growth and water scarcity. The current work investigates the energetic performance of a hybrid absorption refrigeration and desalination system. A parametric study for the system operating conditions has been performed to get the optimal conditions. Also, economic analysis and a multi-objective optimization method are used with the aim of maximizing the energy utilization factor of the system and minimizing total costs. The specific cost of desalinated water from the multi-objective optimization is calculated as (1.728 Cent/L) with the greatest energy utilization factor of (2.214). It turns out that, the system performs optimum at condensation and generation temperatures of 30 and 65 °C respectively, with resultant COP and GOR of 0.84 and 1.37. Using the optimum conditions, TRNSYS has been used to investigate the transient performance of the system for Marsa–Matrouh City in Egypt. The cooling and freshwater demands are 10 kW and 24 L/h. It was concluded that the input energy required to run the hybrid system decreased by about 65% less than that required for separate systems. With the assistance of solar energy, it became clear that the energy required was 60% less than the hybrid system as well.

Transforming CO2 into Synthetic Fuels: Modeling, Simulation, and Optimization Analysis of Methanol Production from Industrial Wastes

Carbon capture and utilization (CCU) has emerged in recent years as a promising decarbonization solution for hard-to-abate industries. Compared to carbon capture and storage (CCS), CCU aims not for the storage of carbon dioxide (CO2) but for its use in the production of synthetic fuels, such as synthetic methanol (MeOH). Synthetic MeOH is produced through CO2 hydrogenation, utilizing green hydrogen (H2). Efficient use of CO2 and H2 feedstocks is essential to maximize the carbon reduction potential and energy efficiency of the process. This study performed an optimization analysis on a small-scale, containerized, and portable CO2 hydrogenation unit with a 5 kg MeOH/h production capacity goal, focusing on carbon conversion efficiency (CCE), MeOH yield, H2 consumption, and MeOH purity. The analysis was conducted using Aspen Plus V12. A single-pass model was used first to evaluate an initial reactor design. The reactor was then re-designed according to the results of the gas hourly space velocity (GHSV). The model was then expanded to include a recycling loop and the final reactor design was validated, aiming to maximize overall efficiency. The effects of the operational parameters including the reactor inlet temperature, reactor pressure, thermal fluid temperature, and condensation temperature were examined. The model was then further expanded to include the MeOH distillation process, and the effect of the distillation temperature was examined. The final product of the analysis was a fully-defined and optimized unit, achieving an 87.97% CCE and an 84.99% MeOH yield, consuming 1.11 kg H2/h for the production of 5.01 kg MeOH/h of 99.86 wt% purity. This study can provide valuable information and guidelines for designing small-scale, containerized, and portable CO2 hydrogenation units, which can serve as alternative solutions to address issues of H2 production and transportation related to large-scale installations.

A high performance solar-assisted ejector expansion refrigeration cycle for residential air conditioning

Introducing a solar collector between the compressor and condenser of an ejector expansion refrigeration cycle (EErc) can improve the performance of the system by further superheating the refrigerant. Hence, this paper proposes a new configuration of a vapor compression refrigeration system, solar compression-ejector expansion refrigeration cycle (SCEErc) with energy saving in the compressor via an ejector and an evacuated tube solar collector. The performance improvement of the proposed system under a wide range of operating conditions such as condenser and evaporator temperatures, superheating and subcooling degrees, nozzle and diffuser efficiencies, and solar radiation intensities has been evaluated and compared with EErc under the same operational conditions and for four different refrigerants. The results indicate that the coefficient of performance (COP) of the SCEErc increased by 26.53 % compared to the EErc for the solar radiation energy of 0.2 kW. Moreover, exergy analysis results indicate a 59 % increase in the exergy destruction of the condenser in the SCEErc compared to the EErc. This is due to the increase in heat rejected from the condenser to the environment, which can be beneficial if the condenser cooling air outlet is utilized for applications like heat recovery technologies. The R152a, boasting a COP of 3.963, presents itself as a more favorable alternative to R134a.

Evaluating sustainability power plant efficiency: Unveiling the impact of power plant load ratio on holding steam ejector performance

Understanding the role of holding ejectors is essential in the broader context of environmental and sustainability research. Through rigorous analysis, optimization of ejector usage is applied to minimize resource consumption and promote cleaner, more sustainable production methods. However, the design and control strategies of the power plant, including the setpoints and tolerances of various components, can also contribute to the power plant load ratio (PPLR). This study explores the impact of PPLR in the power plant cycle on the holding ejectors performance under various condenser temperatures. For comprehensive analysis, the study employs a comprehensive framework encompassing various indicators such as condensing fluid behavior, energy consumption, exergy destruction, air suction in the condenser, and entrainment ratio. The research unveils key findings, including a notable increase in oblique shocks with rising PPLR and a quantifiable rise in the maximum liquid mass fraction in the condensed regime. Additionally, the analysis reveals numerical relationships, such as a 5 % increase in mass flow rate and a 4.9 % rise in energy consumption with a PPLR increase from 0 to +5 %. Negative impacts on performance, such as a 4.6 % reduction in air extraction flow rate from the condenser, are observed with PPLR changes from 0 to −5%.

Techno-economic comparison of organic fluid between single- and dual-flash for geothermal power generation enhancement

The geothermal energy has become a research focus due to its unique advantages as the renewable energy source. Organic Rankine cycle (ORC) is one of the important technologies for geothermal power generation, but ORC has a large irreversible loss and a low overall efficiency. The organic Rankine single-stage flash cycle (ORSFC) and organic Rankine dual-stage flash cycle (ORDFC) are proposed in this paper, and the corresponding mathematical models are established. The influence of operating parameters on techno-economic performance of three power generation systems is studied. Additionally, the comparison of the techno-economic performance of three power generation systems is conducted. The results show that the lower condensation temperature and pinch point temperature difference of heat exchangers improve the power generation performance. The evaporation temperature and flash temperature can be regarded as equivalent temperatures. Compared with the ORC system, the average increase in net output power of ORSFC and ORDFC systems is 22.87 % and 31.71 %, respectively, while the economic performance decreased by 0.98 % and 6.48 %, respectively. Therefore, it is recommended to use ORSFC as the incomplete evaporation power generation system. The R245fa is the optimal choice for ORC system, while the R601 and R601a are more suitable for ORSFC and ORDFC systems.

Sensitivity analysis on heat pump - mechanical vapor recompression desalination system by recovering waste heat of offshore power converter station

Abstract Offshore wind power converter stations produce massive low-temperature waste heat, which can hardly be used constrained by their offshore location. Therefore, the recovery of the waste heat has been raising widespread concern. Meanwhile, a large amount of fresh water is needed for its cooling system. So, a novel system combining high temperature heat pump and a mechanical vapor recompression system (HP-MVR) was proposed, and sensitivity analysis was performed to optimize it. The heat pump was used to absorb the waste heat and to produce high temperature water. The mechanical vapor recompression system was adopted to produce fresh water and to recover the condensation heat from the steam. In order to determine the impact parameters on the two crucial performance indicators of freshwater production and unit energy consumption, this article introduces a sensitivity analysis method, focusing on analyzing the sensitivity of the three operating parameters of heat pump condensation temperature, saturated water vapor inlet temperature entering the compressor, and freshwater condensation temperature to these two performance indicators. The results show that the sensitivity coefficients of heat pump condensation temperature, saturated water vapor inlet temperature entering the compressor, and freshwater condensation temperature are 1.13, -0.26, and 1.56. So, the freshwater condensation temperature has the most significant effect on freshwater output. Their sensitivity coefficients to unit energy consumption are 1.02, 1.41, and -0.64. The saturated water vapor inlet temperature entering the compressor has the most significant impact on the required power consumption per unit of freshwater. It will give some guidance for the application of low-temperature waste heat in seawater desalination and the reduction of operating costs.

A compositional numerical study of vapor–liquid-adsorbed three-phase equilibrium calculation in a hydraulically fractured shale oil reservoir

The development of carbon capture, utilization, and storage technologies has notably advanced CO2-enhanced oil recovery (EOR) in shale oil reservoirs, which are characterized by abundant nanopores. These nanopores induce unique phase behaviors in hydrocarbons, challenging traditional phase equilibrium calculation methods. This paper presents a novel three-phase thermodynamic model (vapor–liquid-adsorbed three-phase equilibrium calculation) that addresses these challenges by considering the nanopore capillary pressure, critical parameter transitions, and material exchange between the adsorbed and bulk phases. Grounded in the multicomponent Langmuir–Freundlich adsorption equation and the Peng Robinson equation of state, this model is integrated into the MATLAB Reservoir Simulation Toolbox using an embedded discrete fracture model framework, enabling detailed study of CO2 and hydrocarbon phase behaviors within shale oil nanopores. The results reveal that there are significant nano-constrained effects on multicomponent fluid phase behavior, particularly in pores smaller than 20 nm, leading to notable changes in bubble and dew point pressures, as well as critical condensation pressures and temperatures. CO2 injection further complicates the system, enhancing interactions and expanding the coexistence region of the liquid and gas phases on the pressure–temperature diagram, especially across varying pore sizes. Optimization research on CO2 huff and puff technical parameters for shale oil reservoirs suggests the following optimal settings: a CO2 injection rate of 100 t/day, a shut-in time of 30 days, and six huff and puff cycles. The results of this study offer critical insights into CO2-EOR mechanisms in shale oil reservoirs and emphasize the importance of nanopore properties in EOR.

Improvised grey wolf optimizer assisted artificial neural network (IGWO-ANN) predictive models to accurately predict the permeate flux of desalination plants

Effective planning, management, and control of industrial plants and processes have exploded in popularity to enhance global sustainability in recent decades. In this arena, computational predictive models have significantly contributed to plant performance optimization. In this regard, this research proposes an Improvised Grey Wolf Optimizer (IGWO) aided Artificial Neural Network (ANN) predictive model (IGWO-ANN Model-1 to 4) to predict the performance (permeate flux) of desalination plants accurately. For this, the proposed models investigated experimental inputs four: salt concentration & feed flow rate, condenser & evaporator inlet temperatures of the plant. Besides, mean squared error (MSE) and the regression coefficients (R2) have been used to assess the models' accuracy. The proposed IGWO-ANN Model-4 shows strong optimization abilities and provides better R2 = 99.3 % with minimum errors (0.004) compared to existing Response Surface Methodology (RSM) (R2 = 98.5 %, error = 0.100), ANN (R2 = 98.8 %, error = 0.060), GWO-ANN (R2 = 98.8 % error = 0.008), models. The proposed models are multitasking, multilayers, and multivariable, capable of accurately analyzing the desalination plant's performance, and suitable for other industrial applications. This study yielded a promising outcome and revealed the significant pathways for the researchers to analyze the desalination plant's performance to save time, money, and energy.

COMPARATIVE THERMODYNAMIC AND ENVIRONMENTAL ANALYSIS OF VAPOR COMPRESSION REFRIGERATION SYSTEM USING C-PENTANE AS REFRIGERANT

The selection of refrigerant is one of the most important parameters when designing a cooling system. Hydrocarbon refrigerants have low primary energy requirements for effective cooling capacity and favourable thermodynamic properties that reduce both direct and indirect greenhouse gas emissions. In this study, a comparative performance and environmental analysis of the vapor compression refrigeration cycle using C-Pentane as the refrigerant was performed. The cooling performance and environmental effect of C-Pentane has been compared with the cooling performance and environmental effect of R134A, R407C and R404A refrigerants in the cooling system. During the analysis, the cooling system was examined under different operating conditions. The highest coefficient of performance (COP) value in the analysis was 6.485 for the refrigeration cycle using C-Pentane, and this value was obtained at 0 oC evaporator temperature and 25 oC condenser temperature operating condition. According to the Life Cycle Climate Performance (LCCP) analysis for refrigerants, the lowest total emission value belongs to C-Pentane. Direct Emission (DE) value and indirect emission (IE) value of C-Pentane are 57.5 kgCO2 and 24928.04 kgCO2, respectively.

An Amphiphilic Cell-Penetrating Macrocycle for Efficient Cytosolic Delivery of Proteins, DNA, and CRISPR Cas9.

The discovery of safe platforms that can circumvent the endocytic pathway is of great significance for biological therapeutics that are usually degraded during endocytosis. Here we show that a self-assembled and dynamic macrocycle can passively diffuse through the cell membrane and deliver a broad range of biologics, including proteins, CRISPR Cas9, and ssDNA, directly to the cytosol while retaining their bioactivity. Cell-penetrating macrocycle CPM can be easily prepared from the room temperature condensation of diketopyrrolopyrrole lactams with diamines. We attribute the high cellular permeability of CPM to its amphiphilic nature and chameleonic properties. It adopts conformations that partially bury polar groups and expose hydrophobic side chains, thus self-assembling into micellar-like structures. Its superior fluorescence makes CPM trackable inside cells where it follows the endomembrane system. CPM outperformed commercial reagents for biologics delivery and showed high RNA knockdown efficiency of CRISPR Cas9. We envisage that this macrocycle will be an ideal starting point to design and synthesize biomimetic macrocyclic tags that can readily facilitate the interaction and uptake of biomolecules and overcome endosomal digestion.

An Amphiphilic Cell‐Penetrating Macrocycle for Efficient Cytosolic Delivery of Proteins, DNA, and CRISPR Cas9

AbstractThe discovery of safe platforms that can circumvent the endocytic pathway is of great significance for biological therapeutics that are usually degraded during endocytosis. Here we show that a self‐assembled and dynamic macrocycle can passively diffuse through the cell membrane and deliver a broad range of biologics, including proteins, CRISPR Cas9, and ssDNA, directly to the cytosol while retaining their bioactivity. Cell‐penetrating macrocycle CPM can be easily prepared from the room temperature condensation of diketopyrrolopyrrole lactams with diamines. We attribute the high cellular permeability of CPM to its amphiphilic nature and chameleonic properties. It adopts conformations that partially bury polar groups and expose hydrophobic side chains, thus self‐assembling into micellar‐like structures. Its superior fluorescence makes CPM trackable inside cells where it follows the endomembrane system. CPM outperformed commercial reagents for biologics delivery and showed high RNA knockdown efficiency of CRISPR Cas9. We envisage that this macrocycle will be an ideal starting point to design and synthesize biomimetic macrocyclic tags that can readily facilitate the interaction and uptake of biomolecules and overcome endosomal digestion.

Performance Evaluation and Working Fluid Screening of Direct Vapor Generation for Solar ORC Using Low-Global Warming Potential (GWP) Working Fluids

Traditional working fluids used in direct vapor generation for solar organic Rankine cycle (DVG-ORC) systems have a high global warming potential (GWP), making it imperative to find environmentally friendly alternative working fluids for these systems. This paper evaluates the performance of the DVG-ORC system under different operating conditions. By comparing the results of traditional working fluids with those of low-GWP fluids, the feasibility of using low-GWP fluids as alternative working fluids is explored. Additionally, to screen the working fluids suitable for this system further, the system is optimized with net output power as the objective function. The results show that evaporation temperature has different impacts on system performance. R245ca and R1336mzz(Z) exhibit higher net output power at different evaporation temperatures, with R1336mzz(Z) only reducing it by 3.73–5.26% compared to R245ca. However, an increase in condensation temperature negatively affects system performance, leading to a decrease in net output power and various efficiencies. Net output power increases with an increase in mass flow rate, indicating that higher mass flow rates can enhance system performance. The optimization results show that the net output power of low-GWP working fluid R1336mzz(Z) decreases by only 3.44% compared to R245ca, which achieves the maximum net output power. Moreover, among low-GWP working fluids, R1336mzz(Z) demonstrates the highest ORC efficiency and system efficiency, making it the most suitable working fluid for the DVG-ORC system due to its environmental friendliness and safety.

Design of New Heat Pump Dryer System: A Case Study in Drying Characteristics of Kitchen Waste

Existing kitchen waste treatment equipment primarily employs biological cultures for high-temperature fermentation of kitchen waste during the secondary decomposition stage. The temperature inside the fermentation chamber is mainly achieved by heating the air through electric heating tubes. However, this method of electric heating still possesses numerous shortcomings, such as high power consumption and significant energy loss. Given the aforementioned reasons, this article proposes a heat pump drying device specifically designed for the moisture removal process during the fermentation treatment of kitchen waste. This device effectively removes the moisture generated during the fermentation of kitchen waste and assists the electric heating unit in the biomass waste treatment equipment in heating the fermentation chamber, thereby reducing electricity consumption.The closed-loop heat pump drying system can continuously introduce hot, low-humidity air into the fermentation chamber through a circulating fan to remove moisture from kitchen waste.To investigate the dehumidification performance of this device, this article varies the airflow rate of the circulating fan in the heat pump drying system and the inlet water temperature of the plate heat exchanger, achieving changes in the airflow through the dehumidification evaporator and the condensation temperature of the system. Under experimental conditions, the range of the coefficient of performance (COP) achieved by the device is between 3.07 and 5.39; the specific moisture extraction rate (SMER) ranges from 0.62 to 1.81 Kg/(Kw·h), and the moisture removal rate (Mr) ranges from 1.9 Kg/h to 8.2 Kg/h.

Thermodynamic analysis of a hybrid ammonia-water refrigeration cycle with low-temperature solar heat

The performance of a solar-driven single-effect ammonia absorption refrigeration unit was studied numerically and experimentally. The thermal performance and unit operation status of small refrigerators were studied under various designing and operating conditions. A thermodynamic cycle scheme of hybrid ammonia-water refrigeration (HAWR) is proposed to operate in parallel with the compressor and ammonia absorption refrigeration, and the performance of the thermodynamic circulation system is evaluated by considering the thermodynamic coefficient and thermodynamic refrigeration ratio as evaluation indexes. Aspen Plus simulation software was introduced to simulate the HAWR and optimise the operation strategy. The results indicate that adjusting the compressor outlet pressure can stabilise the refrigeration capacity of the ammonia refrigeration system. The optimised working point pressure is 600 kPa, while the corresponding evaporation, condensation, absorption, and generation temperatures are 15 °C, 40 °C, 42 °C, and 85 °C respectively, the thermodynamic coefficient is 0.307, and the thermodynamic refrigeration ratio is 0.443. Under the rated cooling conditions, 44.3 % of the cooling capacity is driven by solar energy, and 55.7 % is driven by electric energy in the optimal working state. Under non-optimal working conditions, the proportion of the cooling capacity driven by electric energy is as high as 79.5 %. Under the conditions of sunny weather and with the absence of the compressor, the cooling capacity increases from 2.5 to 7.5 kW as the radiation intensity increases from 600 to 950 W/m2, while the system performance tends to be stable and the coefficient of performance maintains around 0.738 as the irradiation intensity exceeds 800 W/m2.

Performance analysis of double-stage heat pump and refrigeration cycles

Multistage refrigeration systems are investigated to/enhance the performance of vapor compression refrigeration cycles based on our previous work on multistage low-grade thermal energy conversion. A double-stage heat pump and refrigeration cycles (D-S) is expected to reduce the irreversible loss in the heat exchange process. However, certain characteristics of independently configured systems, namely, compressor power and coefficients of performance (COPs), have not been sufficiently clarified. This study aims to elucidate highly advanced heat pump and refrigeration systems by comparing D-S, a basic single-stage heat pump and refrigeration cycles, and a two-stage compression cycle. D-S shows higher COPs for both the refrigeration and heat pump cycles compared with the other cycles, especially at high thermal conductances. The reduction of the irreversible loss in the heat exchange process is confirmed via the entropy generation rate; in particular, the COP increases with a decrease in the entropy generation rate. The evaporation and condensation temperatures of the refrigerant approach the temperature of the heat source when the thermal conductance exceeds 150 kW/K for the refrigeration cycle. The heat exchangers exergy destruction of D-S is 169 kW, S-S is 189 kW, the two-stage cycle is 184 kW/K when the thermal conductance is 100 kW/K.

Mathematical modelling of pumpkin seed drying in a rotary thermosyphon dryer

ABSTRACT Pumpkin seeds swagger a wealthy vitamin and mineral composition. They contain vitamins (A, B, C, K, D, E), minerals (calcium, selenium, zinc, magnesium, copper, potassium, press, manganese and phosphorus), a few amino acids such as glutamic, linolenic and arginine, and greasy plant acids. The Peclet number includes the peripheral rotation speed of the RTS condenser tube. In our case, the Peclet number reflects how the heat transfer to the grain layer due to convection, when the RTS capacitor rotates, relates to the heat transfer due to the thermal conductivity of the grain layer. Thus, in the first drying period, the determining factors for mass transfer will be the conditions at the phase boundary – the mode of air movement outside the grain, the area of the grain, the surface temperature of the RTS condenser. In total, pumpkin seeds contain 12 essential and eight nonessential amino acids.

Optimal evaporation/condensation temperature determination and experimental validation for electric vehicles

This study explores the potential of heat pump air conditioning systems in enhancing the driving range of electric vehicles (EVs) by optimizing evaporator and condenser temperatures to achieve improved system performance and efficiency. A novel methodology is introduced to determine the optimal temperatures for evaporation and condensation within such a system, seamlessly integrated with a primary return system. The validity of this approach is substantiated through rigorous experimental validation. Under New European Driving Cycle (NEDC) conditions, the heat pump air conditioning system demonstrates superior performance and reduced energy consumption, with optimal evaporator temperatures ranging from −2 °C to 2 °C and condenser temperatures between 57.1 °C and 61.8 °C during summer. Winter conditions are optimized with evaporator temperatures from −16 °C to −12 °C and condenser temperatures between 42.4 °C and 48.8 °C. Additional experiments were conducted to validate system performance in both cooling and heating modes. The results highlight a close alignment between the theoretical model for the primary return air system and actual performance, with less than a 10 % discrepancy in calculated outlet temperatures compared to experimental data across various operating conditions. This correlation validates the theoretical model’s capacity to accurately reflect real-world system behavior.

Comparative analysis of thermodynamic performance of high-temperature absorption heat transformers using various ionic liquids as working pairs

The study investigated six sets of ionic liquid (IL) working pairs based on high-temperature vapor-liquid equilibrium data. These sets were modeled using the NRTL activity coefficient model and integrated into a single-stage absorption heat transformer (AHT) for system cycle simulation analysis. A comparison was made with traditional H2O + LiBr working pairs commonly used in AHTs. The study aimed to assess the feasibility of using IL working pairs in high-temperature AHTs to achieve higher output temperatures when dealing with heat sources exceeding 120 °C. Compared to the traditional H2O + LiBr working pair, which has strong COP and ECOP but a limited temperature range, IL pairs offer advantages under various conditions. For instance, H2O + [HMIM][Cl] and H2O + [BMIM][Br] can operate at higher condensation temperatures, providing broader temperature ranges. H2O + [HMIM][Cl] has a wider operational temperature range, suitable for unstable waste heat sources. It also has the highest optimal ECOP value of 0.64 at 197 °C absorption temperature, and shows good cyclic performance, achieving temperature rises of about 78 °C. ILs can maintain stable COPs and circulation ratios over a wide range of absorption temperatures, thus achieving higher temperature rises or meeting the need for higher absorption temperatures. Notably, although the H2O + IL combination exhibits slightly higher exergy loss than the traditional H2O + LiBr pair when comparing exergy losses in the AHT system among different working pairs, its low corrosiveness, lack of crystallization, and wide operating temperature range make these drawbacks insignificant.

Heating and cooling challenges for electric vehicles: A comprehensive experimental study

An efficient mobile air conditioning (MAC) system using a safe and climate-friendly refrigerant is necessary for human comfort, increasing the vehicle’s energy performance, and reducing the fuel/electricity consumption. In the current work, we perform a drop-in experimental comparison for low GWP alternatives to R134a in reversible MAC systems. The study compares two lower global warming potential (GWP) refrigerants; R456A, a non-flammable refrigerant for R134a direct MAC replacement, and R1234yf, an ultra-low GWP and mildly flammable refrigerant that is the standard for new MAC systems. The system’s operational and energy performance is investigated, simulating a wide range of indoor and outdoor steady-state conditions. The measurements are recorded operating a fully monitored vapour compression test rig that uses secondary circuits to set the target conditions. In the heating mode (heat pump), the evaporation temperatures are set at −10 °C, −5 °C, and 0 °C, and condensation temperatures at 40 °C, 50 °C, and 60 °C. In cooling mode (air conditioning), the condensation temperatures are 37.5 °C, 45 °C, and 52.5 °C and are combined with evaporation temperatures of −7.5 °C, 0 °C, and 7.5 °C. In the heating mode, R456A presented a competitive COP to R134a with a reduction of less than 5 %, more remarkable at lower evaporation temperatures. In the cooling mode, R456A showed the lowest COP at a low condensation temperature. R456A and R1234yf COP are comparable at a higher condensation temperature, which suits the T3 climate conditions.

Comparative multi-objective optimization using neural networks for ejector refrigeration systems with LiBr and LiCl working agents

Education's evolution in the context of energy systems is essential for addressing sustainable energy challenges and developing a workforce equipped for future innovations, emphasizing both formal curricula and informal lifelong learning through successful energy case studies. As the global energy sector transforms to reduce carbon emissions and reliance on fossil fuels, innovations in renewable technologies like solar thermal are pivotal for promoting energy security and economic stability, supported by an educational foundation that fosters awareness and technical skills for sustainable development. Exposure to successful renewable energy systems, such as solar-powered refrigeration, offers an informal educational experience that enhances understanding and supports global educational goals, initiating with the innovative design and optimization of these systems using artificial intelligence (neural networks). Based on this formulation, the current article developed two sustainable energy systems by comparing the refrigeration cycles with two different operating fluids and various arrangements, and multi-objective optimization with an evolutionary genetic algorithm is performed for the proposed systems. The studied systems are refrigeration cycles using an ejector and without an ejector with two working fluids of lithium bromide and lithium chloride. The present work's main aim is to examine the working fluid and refrigeration system arrangements. Energy and economic modeling were performed for the proposed systems, and then parametric analysis and two-objective optimization were extracted. Parameters such as generator temperature, condenser temperature, absorber temperature, and evaporator temperature, which significantly impact the proposed system's performance, have been selected as decision parameters, and parametric analysis has been extracted for them. In addition to the mentioned parameters, diffusion mixing efficiency, nozzle efficiency, and heat exchanger have also been studied in the ejector asset system. To find the best values of decision variables, multi-objective optimization for both arrangements is conducted, and results are presented. The results have indicated that the refrigeration system using lithium chloride working fluid without an ejector achieves a coefficient of performance of 0.766 and a cost of 0.922 $/h at the optimal point, while the system with an ejector yields a higher coefficient of performance (1.047) and a slightly lower cost rate (0.991 $/h). The outcomes of this work can play a critical role for higher education institutions in advancing innovative solutions to pressing energy challenges. Lifelong learning, at the heart of educational innovation, can benefit from the integration of sustainable energy systems as a core component of informal education through the optimization of ejector refrigeration systems.